When creating a media composition, producers and editors often wish to combine original media captured specifically for the new composition with pre-existing material. Examples of such pre-existing material are stock video footage and stock music. Typically, the pre-existing material, or “secondary material,” is identified and acquired during the post-production phase of media composition. Current workflows for incorporating such material involve searching catalogs of material offered by providers of secondary material, identifying the desired material, acquiring rights to use the material, including paying for the material if required, and receiving a copy of the acquired material, commonly by downloading the material over the Internet. Once the material is received, it can be imported into a post production editing system. Such a workflow is cumbersome, involving numerous steps. Furthermore, the process is often wasteful, since a proper evaluation of the effectiveness of the acquired secondary material is only possible once the material has been paid for, downloaded, imported into the editing system, and cut into a sequence. In addition, time-based media clips offered by the secondary material providers have a predetermined duration; an editor may only be interested in using a fragment of a clip, but is required to acquire the entire clip in order to obtain the fragment, with the consequent increase in cost, and download delay.